I'll be honest they're about the only thing in the starter which is getting me interested. The plastic dread is nice but I've got a forgeworld one and I'm getting a couple of Decimators at Games Day this year. I don't use possessed and I've already got plans for making my own chosen using a combination of the Chaos Marines box and the Iron Hands and Iron Warriors conversion kits. So not fussed about them either. Unless there is going to be a small 40k rulebook in there like the Fantasy one then I doubt I'll even bother buying a starter box.
Unless what I've been told about special/limited edition versions turns out to be true and the character is worth having.